1. Field of the Invention
This invention relates to a watch case of the kind comprising a front plate, a middle and a back.
In watches of this kind, the function of the middle is threefold: to position the movement and the dial, to protect the watch from environmental aggressions and to contribute to the aesthetic appearance of the watch. In addition, with water-resistant watches, at least, the middle serves to help to keep sealing gaskets in place.
In practice, the middle is particularly problematic because of the contradictory requirements of its threefold function: the aesthetic and protective aspects are best satisfied with hard materials, while the positioning aspect requires complex and accurate shapes, best achieved with a material that is machinable by cutting tools, or with an easily injectable plastics material.
2. Prior Art
In some known watch cases, a compromise solution has been to use brass for the middle and to coat the latter with chrome. Unfortunately, with use, the chrome layer soon gets scratched.
In other known watch cases, the middle is protected by a cap made of hard material, e.g. tungsten carbide. Such cases are virtually everlasting but have a rather massive aspect and are nonetheless difficult to produce since the cap involves quite complex shapes.